1. Field of the Invention
The present invention relates to an image processing apparatus having an image discrimination function which is suitable for use as or in a copying machine, facsimile machine, reader or electronic file.
2. Description of the Prior Art
An apparatus for discriminating a tonality (property or characteristic of image) of a pixel under consideration by utilizing a density difference in the vicinity of the pixel under consideration, and an apparatus which divides one screen of input pixels into 4.times.4-pixel areas (blocks) and discriminates the tonality block by block, have been known. The former requires 6-bit operations and the latter requires two-dimensional complex operation. Accordingly, they are complex in construction and expensive.